Process for hydrogenation of ketones



Patented May 9, 1939 I 2,158,040

UNITED STATES PATENT OFFICE PROCESS FOR HYDROGENATION OF KETONES JosephBlumenfeld, Paris, France No Drawing. Application October 24, 1938, serial No. 236,781. In France October 14, 1937 Claims. (Cl. 260638) Myinvention relates to an improved process alkali or alcoholate, by actionof carbonic acid for the' liquid phase hydrogenation of aldehydesfollowed by simple filtration. and ketones. As an example, and in orderto facilitate the The favorable action of alkalies in thecataunderstanding of the present description, the

5 lytic hydrogenation of aldehydes and ketones has following proceduremay be employed for the 5 been previously disclosed but, under thecondihydrogenation of acetone: The desired action tions employed by theprior investigators, the may be obtained by the addition of sodiumisohydrogenation necessitated, in order to be efpropylate, which may beprepared by dissolving fected withasufiicient degree of speed,either-the 1.2 grams of sodium in 200 cc. of practically 1 use of ratherhigh pressures and temperatures, anhydrous isopropyl alcohol.Approximately 12 or high proportions of catalyst and solvent, cc. ofthis solution of isopropylate in isopropyl It is on account of this factthat in one of the alcohol and 5 grams of active nickel is added to mostrecently described methods, the hydrogena- 56 g. of acetone, and thehydrogenation is comtion of acetone is accomplished at ordinaryprespleted at ordinary temperature and pressure in sure and temperaturein the presence of active 2 or 3 hours. The conversion is practically 15nickel serving as a catalyst, but only with the use complete. It will beobserved that the amount of a solvent comprising a solution of causticsoda of sodium isopropylate, as given in this example in a largequantity of methyl or ethyl alcohol. is small, namely about 0.003 moleof the isopro- This method presents, for its industrial use, the pylateto 1 mole of acetone.

disadvantage of necessitating separating from the By simple decantation,the isopropyl alcohol hydrogenation product the large volume ofsolformed is separated from the bulk of the catalyst, vent whichaccompanies it. This separation is which latter is suitable for re-usein the process. practically impossible in the case where the prod- Theisopropyl alcohol may be readily freed from uct obtained is isopropylalcohol and the solvent particles of entrained nickel, and its sodiumcon- 5 is ethyl alcohol, and it is very diflicult in the tent, bypassing carbon dioxide gas therethrough,

case where the solvent is methyl alcohol. followed by filtration. Thecarbonate formed It has heretofore been supposed that the hyprecipitatesin the form of a gel which carries drogenation would be impossiblewithout a solwith it the nickel particles. vent and that this is due tothe almost complete The isopropyl alcohol thus purified is in ainsolubility of the caustic soda in the aldehydes condition suitable formost uses. Further purior ketones being treated. It has been supposedfication can, however, easily be accomplished by that, in the absence ofsufficient alcohol to comrectification, which will serve to separateother pletely dissolve the caustic soda, this latter would impuritiesderived from the acetone or from a form a coating on the catalyst andprevents its secondary action of the catalyst, and which may catalyticaction. be present in amounts as high as 5%-6%.

According to the present invention it is not The same process mayadvantageously be apnecessary, in order to assist the catalytichydroplied to other ketones, such as methyl-ethyl kegenation, to employan aqueous solution of an tone, diethyl ketone, acetophenone,benzylidene alkali in a large quantity of alcoholic solvent. In ketone,etc.

40 my process, I utilize an alcoholate soluble in the The process may incertain cases, and with the material being hydrogenated, for example, anpreceding restrictions, be advantageously emalcoholate of sodium orpotassium. In practice ployed with the use of heat, with or withoutpres- I may advantageously employ the alcoholate sure, and the nickelmay be replaced with other which corresponds to the alcohol to beproduced catalysts of known types.

by the hydrogenation. What I claim is: 45

In order to avoid hydrolysis of the alcoholate 1. A process of making analcohol by hydrowith resulting liberation of alkali, the reactiongenation, which comprises reacting hydrogen gas should be carried out ina practically anhydrous from an extraneous source upon a ketone whilemedium. said ketone is in a liquid state, diluted with an Butexperiments have proved that a very small alcohol and mixed with asubstantially smaller 50 amount of water, up to one percent for instanceamount of an alcoholate of an alkali metal, in the case of acetone, maybe tolerated. while in the presence of a hydrogenation catalyst,

Also, according to the present invention, the the reaction mixture beingfree from more than alcohol obtained by hydrogenation, after sepa- 1% ofwater.

65 ration of the catalyst, is preferably freed from 2. A process ofmaking an alcohol by hydrogenation, which comprises reacting hydrogengas from an extraneous source upon a ketone while said ketone is in aliquid state, diluted with the alcohol which is to be produced in thehydrogenation reaction, and mixed with a substantially smaller amount ofan alcoholate of an alkali metal, which alcoholate contains the alcoholradical of the alcohol which is to be produced by hydrogenation of saidketone, and while in the presence of a hydrogenation catalyst, thereaction mixture being free from more than water.

3. A process of making an ialcoholsby :hydrogenation, which comprisesreacting hydrogengas from an extraneous source upon a ketone while,

said ketone is in a liquid state, diluted with the alcohol which is tobe produced in the ihydro-. genation reaction, and mixed with asubstantially smaller amount of an alcoholate of an alkali metal, whichalcoholate contains the alcohol radical of the alcohol .whichzis -to be.produced :by hydrogenation of said :ketone, and whilein .the presenceof a hydrogenation catalyst, the :reaction mixture :being free from morethan i1=%r0f water, and thereafter introducingcarbon dioxide into theliquid reaction product to decompose said ketone islin a liquid state,diluted with the alcohol which is to be produced in the hydrogenationreaction, and mixed with a substantially smaller amount of an alcoholateof an alkali ;:metal, whichalcoholate contains the alcohol radical ofthe alcohol which is to be produced by hydrogenation of said ketone, andwhile in the presence of a hydrogenation catalyst, the reac- ;tion,mixture being ;f-ree from more than about 1% of water. 7

5. In ,a ,process for the liquid phase catalytic hydrogenation ofacetone, the improvement which comprises effecting the hydrogenation of:the acetone while diluted with isopropyl alcohol,

in a solution containing approximately 0.003

moles of an alkali metal isopropylate per mole of acetone.

J OSERH BLUMENFELD.

